1. Field of the Invention
The present invention relates to a self-actuated pressure release valve for use with pressurized fluids or gasses. In particular, the present invention relates to a pressure release valve which may be utilized in handling and storing pressurized fluids or gasses in containers.
2. Prior Art
Self-actuated pressure release valves, being automatic pressure-relieving devices, are not only useful but required in handling and storing of pressurized gasses and liquids. These valves are known in the energy, industrial and aerospace industries.
A pressure release valve should have a number of attributes. The valve should have the ability to maintain an adequate seal while under pressure. Normally the valve will be held in the closed position by a spring The seals or gaskets themselves should be easily replaceable while the valve is in place. Additionally, the valve should be fast opening and self-actuated at a precise set pressure. Finally, when the pressure opens the valve at the set or "pop" pressure, the valve should remain fully open for discharge at the proper flow rate to assure adequate discharge in the event of excessive pressure. An adequate flow rate will prevent a pressure increase during discharge or accumulation. The flow rate is enhanced by a laminar flow through the valve, rather than a turbulent flow.
Indeed, all pressurized tanks or containers are subject to a number of regulations. For instance, all vessels operating in excess of 15 psig must be designed and constructed in accordance with the American Society of Mechanical Engineers (ASME) code, Section VIII, for Unfired Pressure Vessels.
Prior pressure release valves have attempted to address these issues in various ways.
Portis (U.S. Pat. No. 3,035,604) discloses a spring loaded valve having a sloping tapered valve that mates with a sloping valve seat. An overhanging, downwardly extending flange mates with an O-ring and valve seat.
Folmsbee (U.S. Pat. No. 2,599,622) discloses a safety valve wherein the gasket can be replaced while in service. A valve head disc has a downwardly turned lip which forms an opening to receive an O-ring.
Klinkenberg (U.S. Pat. No. 2,834,374) illustrates a pressure relief valve, variations of which are commercially available. An upwardly facing shoulder of the body seals with a circular, flat disk held by a valve member.
Farris (U.S. Pat. No. 2,517,858) recognizes the importance of maintaining an adequate lift or thrust so that the proper flow rate will be maintained once the valve has opened.
It is a principal object and purpose of the present invention to provide a pressure relief valve which will maintain an adequate seal while under pressure and which may be depressurized for replacement of the seals or gaskets while the valve is in place.
It is a further object and purpose of the present invention to provide a valve that will open at a precise pressure over the load pressure and will remain open for discharge at a proper flow rate.
It is an additional object and purpose of the present invention to provide a pressure relief valve that is designed to encourage laminar flow and discourage turbulent flow therethrough.